First things

Put the nominate.csv data in the data subdirectory of pols-209.
Open RStudio.
Set the working directory to pols-209.

Load data and have a quick look

# load data
nominate <- read.csv("data/nominate.csv")

# quick look at data
library(dplyr)
glimpse(nominate)

## Observations: 6,173
## Variables: 6
## $ congress               (int) 100, 100, 100, 100, 100, 100, 100, 100,...
## $ state                  (fctr) USA, ALABAMA, ALABAMA, ALABAMA, ALABAM...
## $ congressional_district (int) 0, 1, 2, 3, 4, 5, 6, 7, 1, 1, 2, 3, 4, ...
## $ party                  (fctr) Republican, Republican, Republican, De...
## $ name                   (fctr) REAGAN, CALLAHAN, DICKINSON, NICHOLS  ...
## $ ideology_score         (dbl) 0.747, 0.358, 0.349, -0.039, -0.203, -0...

Mean of the ideology score

# calculate mean
mean(nominate$ideology_score)

## [1] 0.08724688

Mean of the ideology score for Rs (easy way)

# step-by-step
rep <- nominate$party == "Republican"  # logical vector; TRUE for Rs
head(rep)  # show first six

## [1]  TRUE  TRUE  TRUE FALSE FALSE FALSE

ideology_score_reps <- nominate$ideology_score[rep]  # scores for Rs
head(ideology_score_reps)  # show first six

## [1] 0.747 0.358 0.349 0.253 0.392 0.746

mean(ideology_score_reps)  # mean for Rs

## [1] 0.5454887

Mean of the ideology score for Rs and Ds (quick way)

# all at once
mean(nominate$ideology_score[nominate$party == "Republican"])  # Rs

## [1] 0.5454887

mean(nominate$ideology_score[nominate$party == "Democrat"])  # Rs

## [1] -0.3351859

Mean of the ideology score for Rs and Ds for 100th and 113th Congresses

# all at once
mean(nominate$ideology_score[nominate$party == "Republican" & nominate$congress == 100])  # Rs, 100th

## [1] 0.3165556

mean(nominate$ideology_score[nominate$party == "Republican" & nominate$congress == 113])  # Rs, 113th

## [1] 0.7270549

mean(nominate$ideology_score[nominate$party == "Democrat" & nominate$congress == 100])  # Rs, 100th

## [1] -0.2997308

mean(nominate$ideology_score[nominate$party == "Democrat" & nominate$congress == 113])  # Rs, 113th

## [1] -0.3721133

Standard deviation of the ideology score for Rs and Ds for 100th and 113th Congresses

# all at once
sd(nominate$ideology_score[nominate$party == "Republican" & nominate$congress == 100])  # Rs, 100th

## [1] 0.1712619

sd(nominate$ideology_score[nominate$party == "Republican" & nominate$congress == 113])  # Rs, 113th

## [1] 0.1762492

sd(nominate$ideology_score[nominate$party == "Democrat" & nominate$congress == 100])  # Rs, 100th

## [1] 0.1596674

sd(nominate$ideology_score[nominate$party == "Democrat" & nominate$congress == 113])  # Rs, 113th

## [1] 0.1130054

Description

First things

Load data and have a quick look

Mean of the ideology score

Mean of the ideology score for Rs (easy way)

Mean of the ideology score for Rs and Ds (quick way)

Mean of the ideology score for Rs and Ds for 100th and 113th Congresses

Standard deviation of the ideology score for Rs and Ds for 100th and 113th Congresses

Mean for both parties and all Congresses

Standard deviation for both parties and all Congresses